In recent years, services such as a social networking service (SNS) in which contents are shared between specific users have increased in number. In addition, as a result of contents of high image quality being created based on the advanced functions of terminals, the sizes of shared contents tend to become enlarged and a waiting time taken for upload or download of a content tend to become increased.
As a method for reducing the waiting time taken for upload or download of a content, a method utilizing cache servers has been widely utilized. While being targeted at, for example, contents referenced by many and unspecified users under the control of a cache server, a content whose reference count is high is deployed in the cache server. From this, it is possible for a user under the control of that cache server to reduce a time taken to download a content.
There is proposed, for example, a content distribution system that includes a content server installed on a network and cache servers. In this system, while content data stored in the content server is temporarily stored on the cache servers, the content data is distributed to client terminals. In this system, each cache server sorts processing operations for requests into the content server or another cache server in accordance with the state of the relevant cache server itself, the states of the other cache servers, and the types of request or the amount of requests.
In addition, there is proposed a content providing method that distributes a content reserved to be acquired, to a mobile terminal at a predetermined timing. In this method, a content is stored in a temporary storage unit that satisfies a geographical condition or a temporal condition at the time of distributing the content and the content is distributed to the mobile terminal at a timing that satisfies a temporal condition.
As documents of the related art, there are Japanese Laid-open Patent Publication No. 2006-171822 and Japanese Laid-open Patent Publication No. 2002-49766.